U.S. Pat. No. 3,825,396 concerns a blow mold device comprising mold halves mounted on arms which are pivotally arranged for a swinging motion about a vertical column. After closing the mold halves, the free ends of the arms or, respectively, the mold halves are mechanically latched together to prevent separating the mold by the blowing pressure. The arms are subjected to substantial bending forces in the portion between the latching assembly and the pivot axis. This results in large cross-sections of the apparatus and a large inert mass to be moved.
Similar aspects apply to another prior device according to German Application No. 19 66 634 providing for a number of mold halves which are mounted adjacent each other on beams which are mounted for rotation about an axis and which beams are latched together at their free ends by a locking assembly.
Still further, German Patent Specification No. 29 50 723 refers to a drive means for blow mold halves, according to which the carrier of the blow mold is moved longitudinally with respect to the blow mold to obtain thereby the opening and closing motion of the mold halves by cam means provided in a stationary plate. Again, to open and close the mold halves and the carrier, large inert masses have to be accelerated and decelerated.
According to a still further prior construction, substantial weight may be saved when the mold halves are latched together by a cone or a bell which is slipped over the mold. The latching force is thus exerted by a ring-shaped member which is subjected to tensional forces and which is of extremely light weight. However, this applies for mold halves of relatively small diameter as for larger molds the diameter of the bell becomes too large. Further, the bell has to perform a substantial stroke in closing so that the advantages of the light-weight construction and the fast actuation of the mold device are lost.